A hybrid vehicle runs on two types of motive power, namely the motive power of a motor and the motive power of a gasoline engine. The hybrid vehicle stores, in a battery, (a) the electric power produced by the motive power of the gasoline engine and (b) the electric energy obtained by conversion from the kinetic energy of the vehicle through the actuation of a regeneration brake at the time of actuation of an engine brake upon release of the acceleration. However, since the hybrid vehicle runs at a constant speed during travel along the expressway, the electric power produced by the actuation of the regenerative brake is little.
An electric vehicle runs on the electric power of a battery as a source of motive power. The electric vehicle stores, in a battery, the electric energy obtained by conversion from the kinetic energy of the vehicle through the actuation of a regeneration brake at the time of actuation of an engine brake upon release of the acceleration. However, the electric vehicle suffers from the disadvantage of further consumption of electric power during use of air-conditioning and heating equipment, a headlamp, etc. Under such circumstances, there have been demands for improvement in fuel efficiency of hybrid or electric vehicles, in addition to the actuation of the regeneration brake at the time of actuation of the engine brake.